On average 105 students per section from the four sections ‘P’, ‘Q’, ‘R’ and ‘S’ passed an examination. The ratio of total number of students in the sections ‘P’, ‘Q’ and ‘R’ is 3:4:6, respectively and the average of number of students in sections ‘R’ and ‘S’ is 195. If 70% of the total number of students in given four sections passed the examination, then find the total number of students in section ‘Q’.

Given, the average number of students who passed the examination per section is 105. Total number of students who passed the examination from all the sections together = 105 × 4 = 420 Let the number of students in sections ‘P’, ‘Q’ and ‘R’ are ‘3x’, ‘4x’ and ‘6x’, respectively. Number of students in section ‘S’ = 2 × 195 – 6x = (390 – 6x) According to the question; (70/100) × {3x + 4x + 6x + 390 – 6x} = 420 Or, (7/10) × {7x + 390} = 420 Or, 7x + 390 = 600 Or, 7x = 210 Or, x = 30 Number of students in section ‘Q’ = 4 × 30 = 120